Preparation, quality control, biological evaluation, and human absorbed dose estimation of 188Re-HYNIC-TOC

Abstract

Abstract In this study, concerning the advantages of rhenium-188 over other therapeutic radionuclides, such as its stock availability from 188W/188Re generator and radiolabeled peptide therapy in the treatment of patients with widespread disease, preparation and quality control of 188Re-HYNIC-TOC were studied. Optimized conditions for radiolabeling of HYNIC-TOC with 188Re were assessed by several experiments. 188Re-HYNIC-TOC was prepared with radiochemical purity >97%. The radiolabelled compound showed high stability both in PBS buffer and in human serum even after 24 h. Biodistribution of the complex in male Wistar rats was examined up to 24 h after intravenous injection and indicated fast blood clearance and significant accumulation in the kidney. The radiation absorbed dose assessment resource (RADAR) method was used to estimate the equivalent and effective absorbed dose of human organs. Kidney received the absorbed dose of 0.72 mSv/MBq, the highest estimated amount, after injection of the complex. The results showed fast preparation, easy quality control, and relatively similar biodistribution of 188Re-HYNIC-TOC to other peptides. This complex can be considered as an agent for the treatment of patients with medium-sized tumors expressing somatostatin receptors. However, more biological studies are still needed.